1. Field of the Invention
The invention relates in general to an injection locked frequency divider, and more particularly to an injection locked frequency divider using a Hartley voltage controlled oscillator or a Colpitts voltage controlled oscillator.
2. Description of the Related Art
With the development of the communication industry, a high-frequency phase lock loop (PLL) has been widely used in various wired and wireless communication systems, such as a frequency synthesizer or a clock generator. In the high-frequency PLL, a high-frequency frequency divider, which is one of the indispensable elements, receives an original signal and divides the frequency of the original signal by one value or multiple values to lower the frequency thereof.
At present, an injection locked frequency divider having a signal injection unit and a voltage controlled oscillator, such as a LC tank oscillator, is frequently adopted to divide the frequency of the injection signal received by the signal injection unit. In the present technology, only the injection locked frequency divider using the cross-coupled LC tank oscillator is provided. However, it is an important subject in the industry to design an injection locked frequency divider circuit, which can use other types of voltage controlled oscillators and can be thus flexibly applied to various occasions.